OK so i need your help. My 2001 Jeep Cherokee 4.0 was stalling a little so I connected a scanner and got a code telling me I had a cylinder #4 misfire. So i went ahead and replaced the spark plugs and the coil pack, turned on the Jeep and it's still stalling. So i hooked up the scanner again and the missfire code was gone but now i have a #2 injector open circuit. I've checked for a short ground on the wiring but found nothing and there's no ground to the injector.

Of course, double check your connections. Switch around the erroring injector and a good one and see if the issue moves with the injector. If it does, replace the injector. If it stays in the same place, look at wiring.

In answer to your question, a PCM is possible but I think it unlikely.

i swap the injetor 3 to 2 and the probem stayed and the code didnt change i have check the wiring from the pcm to the imjector conector and seems to be fine i just ordered a reman ecm hope that solve my problem

Did you fix your problem? I was reading and found others with your same problem, and did the same things you did to try to fix it. They ended up replacing the injector on the misfiring cylinder and it fixed the problem.